US7515323B2 - Actuator, optical scanner and image forming apparatus - Google Patents

Actuator, optical scanner and image forming apparatus Download PDF

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US7515323B2
US7515323B2 US11/873,539 US87353907A US7515323B2 US 7515323 B2 US7515323 B2 US 7515323B2 US 87353907 A US87353907 A US 87353907A US 7515323 B2 US7515323 B2 US 7515323B2
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voltage
frequency
mass portion
beam portions
pair
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US20080094677A1 (en
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Yasushi Mizoguchi
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Seiko Epson Corp
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Seiko Epson Corp
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
    • G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
    • G02B26/0841—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD the reflecting element being moved or deformed by electrostatic means

Definitions

  • the present invention relates to an actuator, an optical scanner and an image forming apparatus.
  • optical scanners used for, for example, laser printers
  • a structure having a torsional resonator which is manufactured by processing a Si substrate with a micromachining technique.
  • the optical scanner employing such the structure can advantageously perform light scanning at higher velocity than one employing a polygon mirror.
  • the actuator as disclosed in, for example, JP-A-2004-191953, has a plate-shaped reflecting mirror, which is supported from either side by a pair of spring portions.
  • the respective spring portion branches off halfway, and a piezoelectric body is provided at each of the bifurcation.
  • voltage is applied to the each of the piezoelectric bodies so as to bend the respective bifurcations to be deformed, thereby allowing the reflecting mirror to rotate while twisting the pair of spring portions as a whole to be deformed.
  • the mirror is allowed to rotate only about one axis extending along the one pair of spring portions as the center axis of rotation. Therefore, when such the actuator is used as an optical scanner, light can be irradiated either in the direction of main scanning or in the direction of sub-scanning. Accordingly, in order to perform both the main scanning and the sub-scanning, two actuator of this type must be used, which disadvantageously involving increase in cost and growth in size.
  • An advantage of the present invention is to provide an actuator, an optical scanner and an image forming apparatus allowing a mass portion to rotate respectively about two axes intersecting with each other while achieving reduction in cost and miniaturization.
  • An actuator includes: a mass portion; a vibrating part having a pair of elastic portions supporting the mass portion; at least one pair of beam portions supporting the vibrating part; a piezoelectric element bonded on each of the beam portions; voltage applying means that applies voltage to each of the piezoelectric elements so that each of the beam portions is bended to be deformed so as to drive the vibrating part, in which the voltage applying means includes: a first voltage generating part that generates first voltage periodically changing with a first frequency; a second voltage generating part that generates second voltage periodically changing with a second frequency different from the first frequency; and a voltage superimposing part that superimposes the first voltage and the second voltage, and in which the voltage superimposed at the voltage superimposing part is applied to each of the piezoelectric elements to allow the mass portion to rotate about the first axis extending along the pair of elastic portions with the first frequency while rotating about the second axis intersecting with the first axis with the second frequency.
  • the first voltage generating part generate two kinds of the first voltage, the two kinds of the first voltage being out of phase with each other by 180°, the voltage superimposing part superimpose each of the two kinds of the first voltage and the second voltage so that the superimposed voltage at the voltage superimposing part is applied corresponding to a pair of the piezoelectric elements.
  • the vibrating part be supported by the at least one pair of beam portions, support the mass portion through the pair of beam portions, and be provided with a frame body having a frame-like shape surrounding the outer periphery of the mass portion.
  • the beam portions be arranged in pairs through the vibrating part on the either side of the vibrating parts.
  • the mass portion have a plate-like shape; and the two pairs of beam portions be arranged in a point symmetrical manner with respect to the center of the mass portion seen in a plan view of the mass portion.
  • each of the beam portions extend in longitudinal direction; and each of the piezoelectric elements extend in the longitudinal direction and telescope in the extension direction of the beam portions to bend the beam portions to be deformed.
  • each of the beam portions extend in parallel with the first axis.
  • each of the piezoelectric elements be arranged across substantially the entire region of the corresponding beam portion in the longitudinal direction.
  • the first frequency be larger than the second frequency.
  • the first frequency be the same as the torsion resonance frequency of the vibrating system constructed by the mass portion and the vibrating part.
  • the mass portion include a light reflecting part having light reflecting properties.
  • the actuator according to the invention can be applied to optical devices such as an optical scanner, an optical switch or a light attenuator.
  • An optical scanner includes: a vibrating part having a mass portion having a light reflecting part having light reflecting properties and a pair of elastic portions supporting the mass portion; at least one pair of beam portions capable of being bended to be deformed and supporting the vibrating part; a piezoelectric element bonded on each of the beam portions; and voltage applying means that applies voltage to each of the piezoelectric elements so that each of the beam portions is bended to be deformed so as to drive the vibrating part and light reflected at the light reflecting part is used for scanning, in which the voltage applying means includes: a first voltage generating part that generates a first voltage periodically changing with a first frequency; a second voltage generating part that generates a second voltage periodically changing with a second frequency different from the first frequency; and a voltage superimposing part that superimposes the first voltage and the second voltage; and in which the superimposed voltage at the voltage superimposing part is applied to each of the piezoelectric elements to allow the mass portion to rotate about the first axis extending along
  • An image forming apparatus includes: a vibrating part having a mass portion having a light reflecting part having light reflecting properties and a pair of elastic portions supporting the mass portion; at least one pair of beam portions capable of being bended to be deformed and supporting the vibrating part; a piezoelectric element bonded on each of the beam portions; light irradiating means that irradiates the light reflecting part with light; and voltage applying means that applies voltage to each of the piezoelectric elements so that each of the beam portions is bended to be deformed so as to drive the vibrating part and light reflected at the light reflecting part is used for scanning to form image on an object, in which the voltage applying means includes: a first voltage generating part that generates a first voltage periodically changing with a first frequency; a second voltage generating part that generates a second voltage periodically changing with a second frequency different from the first frequency; and a voltage superimposing part that superimposes the first voltage and the second voltage; and in which the superimposed voltage at the voltage superimposing
  • FIG. 1 is a plan view showing an actuator according to an embodiment of the invention.
  • FIG. 2A is a sectional view taken along with the line A-A of FIG. 1 .
  • FIG. 2B is a sectional view taken along with the line B-B of FIG. 1 .
  • FIG. 3 is a sectional view taken along with the line C-C of FIG. 1 .
  • FIG. 4 is a block diagram illustrating the configuration of a control system of the actuator shown in FIG. 1 .
  • FIG. 5A is a view showing an exemplary generated voltage of a first voltage generating part and a second voltage generating part shown in FIG. 4 .
  • FIG. 5B is a view showing an another exemplary generated voltage of a first voltage generating part and a second voltage generating part shown in FIG. 4 .
  • FIG. 5C is a view showing a further exemplary generated voltage of a first voltage generating part and a second voltage generating part shown in FIG. 4 .
  • FIG. 5D is a view showing a yet further exemplary generated voltage of a first voltage generating part and a second voltage generating part shown in FIG. 4 .
  • FIG. 6 is a schematic view showing an example of an image forming apparatus (imaging display) according to the invention.
  • FIG. 7 is a block diagram showing a configuration of a control system of the image forming apparatus shown in FIG. 6 .
  • FIG. 1 is a plan view of an actuator according to an embodiment of the invention
  • FIG. 2A is a sectional view taken along with the line A-A of FIG. 1
  • FIG. 2B is a sectional view taken along with the line B-B of FIG. 1
  • FIG. 3 is a sectional view taken along with the line C-C of FIG. 1
  • FIG. 4 is a block diagram illustrating the configuration of a control system of the actuator shown in FIG. 1
  • FIG. 5A through FIG. 5D are views each showing an exemplary generated voltage of a first voltage generating part and a second voltage generating part shown in FIG. 4
  • FIG. 6 is a view showing an exemplary voltage to be applied to each of piezoelectric elements of the actuator shown in FIG. 1 .
  • the near side of the page plane of FIG. 1 will be referred to as “upside”, the far side of the page plane thereof “downside”, the right side thereof “right” and the left side thereof “left”.
  • the upside of FIG. 2 and FIG. 3 will be referred to as “upside”, the downside thereof “downside”, the right side “right” and the left side “left”.
  • the actuator 1 includes a base 2 having a vibrating part including a one-degree-of-freedom vibrating system, and a supporting substrate 3 supporting the base 2 .
  • the actuator 1 further includes piezoelectric elements 41 , 42 , 43 , 44 that drive the vibrating part 21 of the base 2 .
  • the base 2 has the vibrating part 21 including a one-degree-of-freedom vibrating system and two pairs of beam portions 22 , 23 , 24 , 25 that support the vibrating part 21 , and a supporting part 26 supporting the vibrating part 21 through those beam portions 22 , 23 , 24 , 25 .
  • the vibrating part 21 has a mass portion 211 , a pair of elastic portions 212 , 213 that support the either side of the mass portion 211 , and a frame body 214 supporting the pair of elastic portions 212 , 213 .
  • the mass portion 211 has a plate-like shape (disk-like shape in this embodiment). Near the upper surface of the mass portion 211 (the surface opposite to the supporting substrate 3 ), there is provided a light reflecting part (mirror part) having light reflective properties.
  • the actuator 1 can be applied to optical devices such as an optical scanner, a light attenuator or an optical switch.
  • the mass portion 211 as thus described above is supported by the frame body 214 through the pair of elastic portions 212 , 213 .
  • the frame body 214 has a frame-like shape (a substantially rectangular annular shape in this embodiment) surrounding the outer periphery of the mass portion 211 . That is to say, the frame body 214 has a frame-like shape.
  • the mass portion 211 is provided at the inner side of the frame body while being spaced apart therefrom.
  • the pair of elastic portions 212 , 213 connect the mass portion 211 to the frame body 214 in a rotatable manner.
  • the pair of elastic portions 212 , 213 can be elastically deformable, extend longitudinally, are provided coaxially to each other and support the mass portion 211 from the ether side.
  • the pair of elastic portions 212 , 213 thus constructed make it possible to rotate the mass portion 211 with respect to the frame body 214 in such a way that the elastic portions 212 , 213 serve as a central axis of rotation to be torsionally deformed about a first axis X. That is to say, the vibrating part 21 has a one-degree-of-freedom vibrating system constructed by the mass portions 211 and the pair of elastic portions 212 , 213 .
  • the frame body 214 of the vibrating part 21 as thus described above is supported by a supporting part 26 through the two pairs of beam portions 22 , 23 , 24 , 25 . That is to say, the frame body 214 and the two pairs of beam portions 22 , 23 , 24 , 25 form a vibrating system.
  • the pair of beam portions 22 , 23 are provided one the one side of the vibrating part 21 and the pair of beam portions 24 , 25 are provided on the other side of the vibrating part 21 .
  • Those beam portions 22 , 23 , 24 , 25 are arranged in a point symmetrical manner with respect to the center of the mass portion 211 seen in a plan view of the mass portion 211 of the vibrating part 21 .
  • the supporting part 26 is formed so as to surround the outer periphery of the above-mentioned vibrating part 21 .
  • the pair of beam portions 22 , 23 connect the vibrating part 21 (specifically, the frame body 214 ) and the supporting part 26 .
  • the pair of beam portions 24 , 25 connect the vibrating part 21 (specifically, the frame body 214 ) and the supporting part 26 .
  • Each of the beam portions 22 , 23 , 24 , 25 can be elastically deformed, has a longitudinal shape and extends in parallel with the center axis X of rotation of the mass portions 211 .
  • the two pairs of beam portions 22 , 23 , 24 , 25 make it possible to rotate the frame body about a second axis (center axis of rotation) Y in such a way that the beam portions 22 , 25 and the beam portions 23 , 24 are bended in the opposite directions to be deformed.
  • the base 2 having the vibrating part 21 as thus described above is made from, for example, silicon as a main material.
  • the vibrating part 21 , the beam portions 22 , 23 , 24 , 25 and the supporting part 26 are integrally formed.
  • a piezoelectric element 41 is formed on the beam portion 22 , a piezoelectric element 42 on the beam portion 23 , a piezoelectric element 43 on the beam portion 24 and a piezoelectric element 44 on the beam portion 25 .
  • the piezoelectric elements 41 , 42 and the piezoelectric elements 42 , 43 are arranged in a point symmetrical manner with respect to the center of the mass portion 211 seen in a plan view of the mass portion 211 of the vibrating part 21 as in the case of the pair of beam portions 22 , 23 and the pair of beam portions 24 , 25 as described above.
  • the piezoelectric elements 41 , 42 are mainly described, for the same thing of the piezoelectric elements 41 , 42 holds for the piezoelectric elements 43 , 44 .
  • the piezoelectric element 41 is bonded on the upper surface of the beam portion 22 and formed so as to telescope in the longitudinal direction of the beam portion 22 . As a result, the piezoelectric element 41 can, due to its telescoping motion, bend the beam portion 22 to be deformed in the vertical direction. Further, the piezoelectric element 42 is bonded on the upper surface of the beam portion 23 and formed so as to telescope in the longitudinal direction of the beam portion 23 . As a result, the piezoelectric element 42 can, due to its telescoping motion, bend the beam portion 23 to be deformed in the vertical direction.
  • the piezoelectric element 41 extends in the longitudinal direction of the beam portion 22 and telescopes in this extending direction, thereby bending the beam portion to be deformed.
  • the piezoelectric element 42 extends in the longitudinal direction of the beam portion 23 and telescopes in the extension direction, thereby bending the beam portion 23 to be deformed. As a result, it makes possible to deform the beam portion 23 by the piezoelectric element 42 more reliably with a relatively simple construction.
  • the piezoelectric elements 41 , 42 thus constructed each have a piezoelectric layer formed from a piezoelectric material as a main material and a pair of electrodes sandwiching the piezoelectric layer.
  • the examples of the piezoelectric materials includes zinc oxide, aluminum nitride, lithium tantalate, lithium niobate, kalium niobate, lead zirconate titanate (PZT), barium titatate and so on. It is also possible to combine one or more of them. It is preferable that at least one of zinc oxide, aluminum nitride, lithium tantalate lithium niobate kalium niobate and lead zirconate titanate be a main part of the piezoelectric material used. By constructing the piezoelectric layer of the piezoelectric element 41 by using such materials, it becomes possible to drive the actuator 1 with higher frequency.
  • the piezoelectric element 41 is arranged such that it covers substantially the entire upper surface of the beam portion 22 . Therefore, the piezoelectric element 41 is arranged across substantially the entire region of the beam portion 22 in the longitudinal direction. As a result, the actuation of the piezoelectric element 41 makes it possible to bend the beam portion 22 more widely to be deformed.
  • the piezoelectric element 42 is arranged such that it covers substantially the entire upper surface of the beam portion 23 . Therefore, the piezoelectric element 42 is arranged across substantially the entire region of the beam portion 23 in the longitudinal direction. As a result, the actuation of the piezoelectric element 41 makes it possible to bend the beam portion 23 more widely to be deformed.
  • Such the piezoelectric elements 41 , 42 are both provided on the upper surface of the base 2 .
  • the piezoelectric elements 41 , 42 are actuated to perform telescoping motion alternately (that is, the one extends while the other extracts)
  • the pair of beam portions 22 , 23 can be then bended to be deformed in the opposite directions.
  • the piezoelectric elements 43 , 44 are constructed in the same manner as the above-mentioned piezoelectric elements 41 , 42 . Such the piezoelectric elements 43 , 44 are both provided on the upper surface of the base 2 as in the case of the above-described piezoelectric elements 41 , 42 . As a result, when the piezoelectric elements 43 , 44 are actuated to perform telescoping motion alternately (that is, the one extends while the other extracts), the pair of beam portions 24 , 25 can be then bended to be deformed in the opposite directions.
  • the piezoelectric elements 41 , 42 , 43 , 44 thus constructed are connected to a power supply circuit 5 described later (see FIG. 5A through FIG. 5D ) to be supplied with power. It should be noted that the power supply circuit 5 will be described later in details.
  • the supporting substrate 3 supporting the above-mentioned base 2 is made from, for example, glass or silicon as a main material and bonded to the base 2 .
  • the supporting substrate 3 and the base 2 may be bonded to each other through the intermediation of a bonding layer made mainly from, for example, glass, silicon or SiO 2 .
  • an opening 31 is formed in the part of the supporting substrate 3 corresponding the vibrating part 21 .
  • the opening 31 forms a run off preventing the vibrating part 21 from contacting the supporting substrate at the time of vibration.
  • the opening (run off) 31 is provided, it is possible to prevent the upsizing of the actuator 1 as a whole while making it possible to set the swing angle (vibration) of the vibrating part 21 (of, for example, the mass portion 211 and the frame body 214 ) to be larger.
  • run off is not necessarily opened (as an aperture) at the lower surface of the supporting substrate 3 (the surface opposite to the vibrating part 21 ) when with this construction the above-described effects can be sufficiently achieved.
  • the run off may also be substituted by a recess formed on the upper surface of the supporting substrate 3 .
  • the power supply circuit 5 serving as a voltage applying unit that applies voltage to the piezoelectric elements 41 , 42 , 43 , 44 .
  • the power supply circuit 5 has a first voltage generating part 51 that generates first voltage used for rotating the mass portion 211 about the first axis X, a second voltage generating part 52 that generates second voltage used for rotating the mass portion 211 about the second axis Y, and a voltage superimposing part 53 that superimposes the first voltage and the second voltage to be applied to the piezoelectric elements 41 , 42 , 43 , 44 .
  • the first power generating part 51 generates voltage (voltage for horizontal scanning) that periodically changes with a period T 1 .
  • the first voltage generating part 51 generates two kinds of first voltage V 11 , V 12 that change periodically with frequency (1/T 1 ).
  • the first voltage generating part 51 generates as horizontal scanning voltage (horizontal scanning drive signal) applied to the piezoelectric elements 41 , 42 the first voltage V 11 that changes periodically with the period T 1 , as shown in the right side of FIG. 5A and FIG. 5B .
  • the first voltage V 11 has a wave form similar to a sine wave. Therefore, the actuator 1 can perform main scanning of light effectively. It should be noted that the wave form of the first voltage V 11 is not limited thereto.
  • the first frequency (1/T 1 ) is not particularly limited as long as it is suitable for horizontal scanning; however, it preferably is 10-40 kHz. Further, it is preferable to set the first voltage to be substantially the same as a torsion resonance frequency of the vibrating system constructed by the mass portion 211 and the elastic portions 212 , 213 . In other words, the torsion resonance frequency of the vibrating system constructed by the mass portion 211 and the elastic portions 212 , 213 is preferably designated to be the same as the frequency that is suitable for horizontal scanning.
  • the first voltage generating part 51 generates as horizontal scanning voltage (horizontal scanning drive signal) applied to the piezoelectric elements 43 , 44 first voltage V 12 that changes periodically with the period T 1 as shown in the right side of FIG. 5C and FIG. 5D .
  • the first voltage V 12 has the same wave form as the first voltage V 11 , but has a phase, which is out of phase with the first voltage V 11 by 180°.
  • the second voltage generating part 52 generates voltage (voltage for vertical scanning) that changes periodically with a period T 2 , which is different from the period T 1 , as shown in the left side of FIG. 5A through FIG. 5D . That is to say, the second voltage generating part 52 generates second voltage V 21 , V 22 that change periodically with two kinds of frequency (1/T 2 ), which is different from the first frequency (1/T 1 ).
  • the second voltage generating part 52 generates as vertical scanning voltage (vertical scanning drive signal) applied to the piezoelectric elements 41 , 43 the second voltage V 21 that changes periodically with the period T 2 , which is different from the period T 1 , as shown in the left side of FIG. 5A and FIG. 5C .
  • the second voltage V 21 has a wave form similar to a saw tooth wave. Therefore, the actuator 1 can perform sub-scanning of light effectively. It should be noted that the wave form of the second voltage V 21 is not limited thereto.
  • the second frequency (1/T 2 ) is not particularly limited as long as it is different from the first frequency (1/T 1 ) and suitable for vertical scanning; however, it preferably is smaller than the first frequency (1/T 1 ). That is to say, the period T 2 is preferably longer than the period T 1 .
  • the second frequency (1/T 2 ) is preferably 40-80 Hz (approximately 60 Hz), thereby making it possible to rotate the mass portion 211 respectively about the two axes intersecting with each other (the first axis X and the second axis Y) with a frequency suitable for performing drawing on a display.
  • the second voltage generating part 52 generates as vertical scanning voltage (vertical scanning drive signal) applied to the piezoelectric elements 42 , 44 second voltage V 22 that changes periodically with the period T 2 as shown in the left side of FIG. 5B and FIG. 5D .
  • the second voltage V 22 has the same wave form as the second voltage V 21 ,
  • the first voltage generating part 51 and the second voltage generating part 52 thus constructed are both connected to a control part (synchronizing signal generating circuit) and driven on the basis of signals from the control part 6 .
  • the voltage superimposing part 53 is connected to the first voltage generating part 51 and the second voltage generating part 52 .
  • the voltage superimposing part 53 has an adder 531 that is used for applying voltage to the piezoelectric element 41 , an adder 532 that is used for applying voltage to the piezoelectric element 42 , an adder 533 that is used for applying voltage to the piezoelectric element 43 and an adder 534 that is used for applying voltage to the piezoelectric element 44 .
  • the adder 531 receives first voltage V 11 from the first voltage generating part 51 and second voltage V 21 from the second voltage generating part 52 to superimpose those voltages and apply the superimposed voltage to the piezoelectric element 41 .
  • the adder 532 receives first voltage V 11 from the first voltage generating part 51 and second voltage V 22 from the second voltage generating part 52 to superimpose those voltages and apply the superimposed voltage to the piezoelectric element 42 .
  • the adder 532 receives first voltage V 11 from the first voltage generating part 51 and second voltage V 22 from the second voltage generating part 52 to superimpose those voltages and apply the superimposed voltage to the piezoelectric element 42 .
  • the adder 533 receives first voltage V 12 from the first voltage generating part 51 and second voltage V 21 from the second voltage generating part 52 to superimpose those voltages and apply the superimposed voltage to the piezoelectric element 43 .
  • the adder 534 receives first voltage V 12 from the first voltage generating part 51 and second voltage V 22 from the second voltage generating part 52 to superimpose those voltages and apply the superimposed voltage to the piezoelectric element 44 .
  • the actuator 1 thus constructed is driven as follows:
  • the voltages V 11 and V 21 as shown in FIG. 5A are superimposed to be applied to the piezoelectric element 41
  • the voltages V 11 and V 22 as shown in FIG. 5B are superimposed to be applied to the piezoelectric element 42
  • the voltages V 12 and V 21 as shown in FIG. 5C are superimposed to be applied to the piezoelectric element 43
  • the voltages V 12 and V 22 as shown in FIG. 5D are superimposed to be applied to the piezoelectric element 44 .
  • the state in which the piezoelectric elements 41 , 42 extend and the piezoelectric elements 43 , 44 are contracted with the first period (1/T 1 ) and the state in which the piezoelectric elements 41 , 43 extend and the piezoelectric elements 42 , 44 are contracted with the second period (1/T 2 ) are alternately repeated.
  • the ration of the range, within which the piezoelectric elements 41 , 43 can telescope (the length, across which the piezoelectric elements 41 , 43 can displace,), and the range, within which the piezoelectric elements 42 , 44 can telescope (the length, across which the piezoelectric elements 42 , 44 can displace) is made to change with the second period (1/T 2 ), while the piezoelectric elements 41 , 42 and the piezoelectric elements 43 , 44 are made to extend in the opposite directions with the first period (1/T 1 ).
  • the piezoelectric elements 41 through 44 thus operate, mainly the respective beam portions 22 , 23 , 24 , 25 are bended to be deformed while the mass portion 211 rotates (vibrates) about the first axis X with the first frequency (1/T 1 ) and about the second axis Y with the second frequency (1/T 2 ).
  • the voltage superimposed by the voltage superimposing part 53 is applied to the respective piezoelectric elements 41 , 42 , 43 , 44 , thereby making the mass portion 211 to rotate about the first axis X, which extends along the pair of elastic portions 212 , 213 , with the first frequency (1/T 1 ) while rotating about the second axis Y intersecting with the first axis X with the second frequency (1/T 2 ).
  • the frame body 214 which has a frame-like shape and surrounds the outer periphery of the mass portion 211 , is supported by the two pairs of beam portions 22 , 23 , 24 , 25 and supports in turn the mass portion 211 through the pair of elastic portions 212 , 213 .
  • the mass portion 211 it becomes possible to allow the mass portion 211 to rotate about the first axis X, which extends along the pair of elastic portions 212 , 213 , with the first frequency (1/T 1 ) while rotating about the second axis Y with the second frequency (1/T 2 ) with lower power and more smoothly.
  • each of the pair of the beam portions is arranged at the either side of the vibrating part through the same.
  • the two pairs of beam portions 22 , 23 , 24 , 25 are arranged in a point symmetrical manner with respect to the center of the mass portion 211 seen in a plan view of the mass portion 211 .
  • each of the piezoelectric elements 41 , 42 , 43 , 44 extends in the longitudinal direction of the beam portion 23 and telescopes in the extension direction, thereby bending the beam portions 22 , 23 , 24 , 25 to be deformed.
  • the mass portion 211 it becomes possible to allow the mass portion 211 to rotate about the first axis X, which extends along the pair of elastic portions 212 , 213 , with the first frequency (1/T 1 ) while rotating about the second axis Y with the second frequency (1/T 2 ) with lower power and larger rotating angle.
  • each of the beam portions 22 , 23 , 24 , 25 extends in parallel with the first axis X, so the actuator 1 can be further downsized while making the rotating angle of the mass portion 211 larger.
  • the respective piezoelectric elements 41 , 42 , 43 , 44 are arranged across substantially the entire region of the corresponding beam portions 22 , 23 , 24 , 25 in the longitudinal direction. As a result, the actuator 1 can be further downsized while making the rotating angle of the mass portion 211 larger.
  • the actuator 1 as thus described above can be preferably applied to an optical scanner provided in an image forming apparatus such as a laser printer, a barcode reader, a confocul scanning laser microscope or a display for imaging.
  • an image forming apparatus such as a laser printer, a barcode reader, a confocul scanning laser microscope or a display for imaging.
  • the actuator 1 is used as an optical scanner for a display for imaging as an example of the image forming apparatus with reference to FIG. 6 and FIG. 7 .
  • FIG. 6 is a schematic view illustrating an example of the image forming apparatus (imaging display) according to the invention
  • FIG. 7 is a block diagram illustrating a configuration of the control system of the image forming apparatus shown in FIG. 6 .
  • the image forming apparatus 10 includes the actuator 1 as an optical scanner and a light irradiating apparatus 7 that irradiates the light irradiating apparatus 7 with light and forms image (performs drawing) on a screen 9 by performing main scanning and sub-scanning with light from the light irradiating apparatus 7 by using the actuator 1
  • the screen 9 may be integrated with the main body of the image forming apparatus 10 or be separated therefrom. Further, it is possible to irradiate the front surface of the screen 9 (the visible surface) with light from the light irradiating apparatus 7 thereby producing a screen display, or to irradiate the back surface of the screen 9 (the surface opposite to the visible surface) with light from the light irradiating apparatus 7 thereby allowing light to pass through the surface and producing a screen display thereon.
  • the light irradiating apparatus 7 has three light sources 71 , 72 , 73 respectively for red (R), green (G), blue (B), a cross dichroic prism (X prism) 74 , a mirror 75 , and a lens 76 .
  • the light source 71 generates red light and is connected to a light source driver 81 that drives the light source 71 .
  • the light source 72 generates green light and is connected to a light source driver 82 that drives the light source 72 .
  • the light source 73 generates blue light and is connected to a light source driver 83 that drives light source 73 .
  • Each of the light source drivers 81 , 82 , 83 is connected to a control part 6 A and operates according to signals from the control part 6 A.
  • the control part 6 A receives image information (image signal) from a host computer (not shown) and allows according to the image information each of the light source drivers 81 , 82 , 83 to operate.
  • the control part 6 A controls the drive of the power supply circuit 5 on the basis of behavior information of the actuator 1 (mass portion 211 ) detected by a detecting unit (not shown).
  • the actuator 1 (light reflecting part 215 ) is irradiated with light of each of the colors from each of the light sources 71 , 72 , 73 via the cross dichroic prism 74 , the mirror 75 and the lens 76 .
  • red light from the light source 71 green light from the light source 72 and blue light from the light source 73 are synthesized at the cross dichroic prism 74 .
  • the intensity of light emitted from the light sources 71 , 72 , 73 of each of the colors changes according to image information received from the host computer (not shown).
  • the screen 197 is irradiated with light reflected at the light reflecting part 215 (the synthesized light of three colors).
  • the mass portion 211 of the actuator 1 rotates about the first axis X
  • the light reflected at the light reflecting part 215 is used for performing scanning (main scanning) in the lateral direction of the screen 9 .
  • the mass portion 211 of the actuator 1 rotates about the second axis Y
  • the light reflected at the light reflecting part 215 is used for performing scanning (sub scanning) in the longitudinal direction of the screen 9 .
  • the image forming apparatus 10 performs image forming (drawing) on the screen 9 .
  • image forming apparatus 10 it is possible to perform two dimensional scanning, that is, main scanning (horizontal scanning) and sub-scanning (vertical scanning) by using only one actuator 1 , thereby achieving reduction in cost and miniaturization.
  • the actuator according to the invention has been described above with reference to the embodiment show; however, the present invention is not limited thereto.
  • the actuator according to the invention for example, it is possible to substitute the construction of each of the components with any possible construction, with which the same function can be obtained, or to add any possible construction thereto.
  • the actuator 1 having the tow pairs of beam portions has been described; however, the number of the pair of beam portions may be one or more than three, as long as the beam portions make it possible to allow the mass portion to rotate respectively about two axes intersecting with each other.
  • the form of beam, the size, the arrangement etc. are not limited to those according to the above-mentioned embodiment, as long as the beam portions make it possible to allow the mass portion to rotate respectively about two axes intersecting with each other.
  • the piezoelectric elements are bonded only on the upper surface of the beam portions; however, it should not be construed restrictively.
  • the piezoelectric elements may be bonded on the lower surface of the beam portions.
  • a part of the piezoelectric elements may be bonded on the upper surface of the beam portions and another part of the piezoelectric elements may be bonded on the lower surface of the beam portions.
  • the plural piezoelectric elements are preferably arranged symmetrically with respect to the first axis and/or the second axis.
  • the construction has been described, which is substantially symmetrical (left-right symmetry) with respect to the first axis or the second axis, seen in a plan view; however, an asymmetrical construction may be employed.
  • the construction has been described, in which the light reflecting part is provided on the upper surface (the surface opposite to the supporting substrate) of the mass portion; however, it is possible to employ the construction, in which the light reflecting part is provided on the surface opposite to the supporting substrate of the mass portion, or the construction, in which the light reflecting part is provided on the either surface of the mass portion.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Optical Scanning Systems (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)
  • Facsimile Heads (AREA)
US11/873,539 2006-10-19 2007-10-17 Actuator, optical scanner and image forming apparatus Active 2027-11-28 US7515323B2 (en)

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JP2006-285450 2006-10-19
JP2006285450A JP4400608B2 (ja) 2006-10-19 2006-10-19 アクチュエータ、光スキャナ、および画像形成装置

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JP (1) JP4400608B2 (ja)
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US20100067083A1 (en) * 2008-09-18 2010-03-18 Fujitsu Limited Micro-movable device
US8771085B1 (en) 2010-08-06 2014-07-08 Arthur C. Clyde Modular law enforcement baton
US8867114B2 (en) 2010-01-05 2014-10-21 Funai Electric Co., Ltd. Vibrating mirror element
US9335543B2 (en) 2013-10-29 2016-05-10 Seiko Epson Corporation Optical scanner, image display device, head mount display, and heads-up display

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JP5296427B2 (ja) * 2008-06-20 2013-09-25 キヤノン電子株式会社 光走査装置及びその制御方法、並びに、画像読取装置及びディスプレイ装置
JP4868047B2 (ja) * 2009-09-01 2012-02-01 セイコーエプソン株式会社 アクチュエータ、光スキャナ、および画像形成装置
JP2012198314A (ja) * 2011-03-18 2012-10-18 Ricoh Co Ltd アクチュエータ装置、光偏向装置、光走査装置、画像形成装置及び画像投影装置
JP5299482B2 (ja) * 2011-08-04 2013-09-25 セイコーエプソン株式会社 アクチュエータ、光スキャナ、および画像形成装置
JP5299489B2 (ja) * 2011-09-22 2013-09-25 セイコーエプソン株式会社 アクチュエータ、光スキャナ、および画像形成装置
JP6111532B2 (ja) * 2012-05-11 2017-04-12 セイコーエプソン株式会社 光学デバイス、光スキャナーおよび画像表示装置
JP5942576B2 (ja) 2012-05-11 2016-06-29 セイコーエプソン株式会社 光学デバイス、光スキャナーおよび画像表示装置
JP2014087169A (ja) * 2012-10-24 2014-05-12 Seiko Epson Corp 駆動装置、駆動回路、ロボットハンド、ロボット、電子部品搬送装置、電子部品検査装置、送液ポンプ、印刷装置、電子時計、投影装置
JP5935761B2 (ja) 2013-06-12 2016-06-15 セイコーエプソン株式会社 光学デバイス、光スキャナーおよび画像表示装置
JP6460406B2 (ja) * 2015-06-09 2019-01-30 第一精工株式会社 可動反射素子及び二次元走査装置
EP3220183B1 (en) * 2016-03-17 2021-11-10 Ricoh Company, Ltd. Control unit, optical deflection system, image projection apparatus, and control method
EP3540496A4 (en) * 2016-11-09 2020-09-09 Dai-Ichi Seiko Co., Ltd. MOBILE REFLECTIVE ELEMENT
DE102019001579B3 (de) 2019-03-06 2020-01-30 Physik Instrumente (Pi) Gmbh & Co. Kg Verfahren zum Betreiben eines elektromechanischen Elements, Aktor, Antriebsvorrichtung und Motor

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US20100067083A1 (en) * 2008-09-18 2010-03-18 Fujitsu Limited Micro-movable device
US8320035B2 (en) * 2008-09-18 2012-11-27 Fujitsu Limited Micro-movable device
US8867114B2 (en) 2010-01-05 2014-10-21 Funai Electric Co., Ltd. Vibrating mirror element
US8771085B1 (en) 2010-08-06 2014-07-08 Arthur C. Clyde Modular law enforcement baton
US9335543B2 (en) 2013-10-29 2016-05-10 Seiko Epson Corporation Optical scanner, image display device, head mount display, and heads-up display

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TW200844480A (en) 2008-11-16
CN101165534A (zh) 2008-04-23
CN101165534B (zh) 2010-12-15
JP2008102362A (ja) 2008-05-01
JP4400608B2 (ja) 2010-01-20
US20080094677A1 (en) 2008-04-24
CN101968568B (zh) 2013-03-27
CN101968568A (zh) 2011-02-09

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